Ml I, / 



BULLETIN OF THE 



No. Ill 



Contribution from the Bureau of Entomology, L. O. Howard, Chief. 

 July 11, 1914. 



(PROFESSIONAL PAPER.) 



THE SEQUOIA PITCH MOTH, A MENACE TO PINE 

 IN WESTERN MONTANA. 



By Josef Brunner, 

 Agent and Expert, Forest Insect Investigations. 



INTRODUCTION. 



Ill the area near and at the divide between Swan River and Clear- 

 water River in Montana and extending, so far as known at present, 

 about 8 miles southeast from that divide, the sequoia pitch moth 

 (Vespamima sequoia Hy. Edw.) 1 is at present the most destructive 

 insect. It menaces the lodgepole pine timber, in which it propagates, 

 and all other trees in the vicinity of those attacked are jeopardized 

 by the forest fires fed by the dead timber resulting from the work 

 of its larvse. The range of its peculiar injury to trees in that region 

 has also been traced by the writer about 6 miles west from the wagon 

 road which unites the Clearwater and the Swan River country from 

 Rainy Lake toward the Mission Range. Roughly, the area in which 

 the insect is a very serious factor in forest destruction is about 12 

 miles long by as many miles wide and covers about 144 sections of 

 forest land, or more than 90,000 acres. 



Control and practical elimination of this insect, as a serious menace 

 to the very existence of the forest growth of this area, depends largely 

 on a knowledge of its habits and life history. Insufficient familiarity 

 with these two points would result in unnecessary waste of time in 

 locating infested trees and in conducting control operations at a time 

 of the year when the result would be out of proportion to the cost. 



DESCRIPTION OF THE INSECT. 



Vespamima sequoia (fig. 1) is a clear- winged moth in general appear- 

 ance strongly resembling a hornet or "yellow jacket." This resem- 

 blance is so perfect that a truck gardener near Missoula, Mont., evi- 



1 Identification by August Busck, as the species which was first found to inhabit the sequoia. 

 Note. — This bulletin is a report on an insect infesting lodgepole pine in the Rocky Mountain region of 

 Montana. 



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